Method for combating microorganisms with unsubstituted or bromo-substituted cyclobutanone



United States Patent Chemical Corporation, New York, N.Y., a corporation of New York No Drawing. Filed Aug. 25, 1966, Ser. No. 574,931 8 Claims. (Cl. 167-30) This invention relates to a method for combating microorganisms, especially bacteria, and, in a preferred embodiment, relates to a method of combating microorganisms by treating them with chemical agents in vapor phase.

The problem of combating microorganisms, meaning in the context of this discussion killing and preventing or retarding the propagation of microorganisms, is common to a number of industries such as the food, agricultural and pharmaceutical industries, and is particularly significant to the medical profession. The usual methods of sterilization such as steam, heat, chemical solution, radiation, and the like, are impractical when large areas such as hospital rooms, laboratories and animal quarters are desired to be sterilized or when it is desired to sterilize delicate laboratory and medical equipment, which may contain plastics, fabrics, and the like that may be adversely affected by moisture and heat.

The term sterilization is generally interpreted as referring to a condition in which a body or locus is freed from all living microorganisms as opposed to being freed only from certain microorganisms.

The problem of freeing a body from all living microorganisms is no mean one because, although many varieties of microorganisms are relatively easy to combat, others have particularly high resistances to adverse conditions and are exceedingly difficult to combat. Such a microorganism is the bacteria Staphylococcus aurcus. Unfortunately, such bacteria are commonly found in hospitals and food and .are responsible for a large number of human fatalities every year. Because Staphylococcus aureus cells are so difficult to combat in comparison with other microorganisms, researchers have used these cells as standards for sterilization tests. It is presumed that, if a given chemical agent is effective in combating Staphylococcus aureus cells, it will be effective in combating other varieties of vegetative cells. The converse of this is, of course, not true. Experience has proved this to be the case. An illustrative standard test that is Widely used is the so-called F.D.A. Method (Food and Drug Administration Method) as published by Ruehle and Brewer in 1931. (See Porter, Bacterial Chemistry and Physiology, John Wiley & Sons, Inc., N.Y. (1946), p. 226.) This method requires tests of disinfectant or antiseptic action to be carried out against strains of Staphylm coccus aureus.

The problem of sterilizing large areas and of sterilizing heator water-sensitive materials has been alleviated by the use of antimicrobic agents in vapor phase. Effective vapor phase antimicrobic agents must be capable of being readily introduced into the vicinity of the area to be treated; of rapidly and thoroughly penetrating porous surfaces in the area; of effectively penetrating, while in vapor phase, the microorganisms to be treated; of destroying the microorganisms at normal temperatures and humidities; and of permitting ready removal by aeration. Unfortunately, many chemical agents, while possessing good antimicrobic activity, are not capable of functioning effectively in vapor phase for lack of one or more of the above-noted requirements. Bactericidal agents, for example, which have high vapor pressures and may be 3,336,187 Patented Aug. 15, 1967 vaporized easily, may still not possess the penetrability properties required for effective vapor phase use.

It is a major object of this invention to provide a novel method for combating microorganisms such as bacteria, fungi, and the like.

It is another object of the invention to provide a novel method for effectively combating microorganisms such as bacteria, fungi, and the like, over a wide range of relative humidity conditions.

Yet another object of the invention is to provide a novel sterilization method.

It is a more particular object of the invention to provide a novel method for combating bacteria.

A still more specific object of the invention is to provide a novel method for combating Staphylococcus aureus cells.

A preferred object of the invention is to provide a novel method for combating microorganisms, particularly bacteria, comprising treating them with chemical agents in vapor phase.

The preferred, most specific object of the invention is to provide a novel method for combating Staphylococcus aureus cells by treating them with chemical agents in vapor phase.

It has been found that the above-stated objects of the invention are accomplished by treating microorganisms, particularly Staphylococcus aureus cells, with an unsubstituted or bromo-substituted cyclobutanone of the formula:

the subject cyclobutanones may be used effectively in vapor phase.

The subject cyclobutanones are known compounds. The preparation of cyclobutanone is reported in Rec. Trav. Chim., vol. 70, pages 1033-41 (1951). u-Bromocyclobutanone may be prepared by bromination of cyclobutanone, as disclosed by J. M. Conia and J. L. Rapoli, Compt. Rend., 251, 1071-3 (1960).

The subject cyclobutanones may be used to treat microorganisms by contacting the microorganisms to be treated, or surfaces containing the same, with the subject cyclobutanones in the form of solutions, sprays, mists, dusts, or in accordance with the preferred embodiment, in vaporous state. The subject cyclobutanones may be used alone or in admixture with vaporous, solid or liquid diluents such as air and water or hydrocarbon liquids, with or without any of the well-known anionic, cationic or nonionic surface-active wetting agents. Such agents include, for example, alkali metal salts of higher fatty acids, water-soluble salts of sulfated higher fatty alcohols, water-soluble aryl sul-fonates, and quaternary ammonium bases such as trialkyl :benzyl ammonium chloride. In the preferred vapor phase embodiment, a subject cyclobutanone may be conveniently employed such as by vaporizing it in a closed area in which the microorganism-containing surfaces to be treated are located or by usin a vaporous diluent such as air which may be bubbled into the liquid cyclobutanone and then the cyclobutanone-laden air used to fumigate a closed space surrounding the microorganism-containing surfaces to be treated.

As is well known in this art, dosages of a given antimicrobic agent can vary widely depending upon the particular organism to be controlled, the area of the locus to be treated, the time in which control is desired to be established, and environmental conditions such as temperature, relative humidity, etc. In any event, suflicient concentrations of the subject cyclobutanones should be utilized in order to effectively combat the microorganisms to be treated, that is to say, in order to maximize the killing of existing living bacteria and the prevention of propagation of the same in the same locus for a significant period of time. The dosages that will be required in a particular case to accomplish these ends are readily ascertainable and are thus within the skill of the art.

The subject cyclobutanones can be employed as the sole active ingredient in combating microorganisms; however, if desired, they can be combined with active materials such as other antimicrobic agents or growth inhibitors to achieve special results or with nonactive components such as perfumes, propellant aids, and the like.

EXAMPLE 1 One-tenth ml. portions of cyclobutanone, B.P. 98.5 99 C., were charged to one-liter flasks. Circular patches of cotton cloth, each having an area of about 2 cm. and each impregnated with an aqueous suspension of about 5x10 Staphylococcus aurcus cells and subsequently dried, were suspended by wires about halfway down into the flasks. The flasks were stoppered and the patches containing the bacteria were exposed to the cyclobutanone at temperatures of 80 C. and at 90% relative humidity for a period of 24 hours, during which period vapors of cyclobutanone were evolved. At the end of the exposure periods, the patches were removed and assayed for viable organisms by the pour-plate method as follows: The patches were placed in dilution blanks composed of aqueous solutions of 0.1% lecithin v./v. and 0.71% Tween 80 (trademark of Atlas Powder Co. for an emulsifier comprising a polyoxyalkylene derivative of sorbitan monooleate) v./v. and adjusted to pH 7 with 1 N NaOH. Organisms remaining on the patches were dislodged by shaking and aliquots were plated in enriched nutrient agar. After incubating for 48 hours at 37 C., the percentage of organisms killed (attributable to the subject cyclobutanone test material) was calculated by comparison of the number found after testing with an assay of unexposed contaminant patches. Bacteria counts were made with a Quebec Colony counter. It was found that 100% of the Staphylococcus aurcus cells were killed.

EXAMPLE 2 The procedure of Example 1 was repeated with abromocyclobutanone as the test compound and with the exceptions that duplicate exposures were made at relative humidity with 4 hours of exposure. It was found that at the end of the indicated exposure periods, and at the indicated relative humidities, of the Staphylococcus aurcus cells were killed.

I claim:

1. The method for combating microorganisms which comprises treating said microorganisms with an effective amount of a compound of the formula:

wherein X is H or Br, or mixtures thereof.

2. The method of claim 1 in which the compound is cyclobutanone.

3. The method of claim 1 in which the compound is a bromocyclobutanone.

4. The method of claim 1 in which the compound is employed in vapor phase.

5. The method of claim 1 in which the microorganisms treated are bacteria.

6. The method of claim 5 in which the bacteria are Staphylococcus aureus cells.

7. The method of claim 6 in which the compound is cyclobutanone and in which such material is employed in vapor phase.

8. The method of claim 6 in which the compound is a-bromocyclobutanone and in which such material is employed in vapor phase.

No references cited.

LEWIS GOTTS, Primary Examiner.

SHEP K. ROSE, Assistant Examiner, 

1. THE METHOD FOR COMBATING MICROORGANISMS WHICH COMPRISES TREATING SAID MICROORGANISMS WITH AN EFFECTIVE AMOUNT OF A COMPOUND OF THE FORMULA: 